Fan protection valve

ABSTRACT

Apparatus in a heat transfer system or the like. The open end of a duct normally supplied with air at high flow rates is controlled by a valve biased to a position of minimum restriction. Under conditions of high airflows, a created pressure difference moves the valve toward a position of maximum restriction. A fan, located in the duct to induce air flow in the absence of the normal supply, is protected thereby from damage caused by excessive windmilling.

United States Patent [111 3,556,142

[72] Inventors Leroy J. Sabin [56] References Cited Xenia; UNITED STATESPATENTS App] No ggg'f 3,255,963 6/1966 Gotchev et al. l38/46X Filed y1969 3,406,904 10/1968 Muzzl et al. 165/126X [45] Patented Jan. 19, 1971Primary Examiner-William R. Cline [73] Assignee United AircraftProducts, Inc. ArtrneyJ E. Beringer Dayton, Ohio a corporation of Ohio[54] FAN PROTECTION VALVE 7 Claims, 2 Drawing Figs. [52] US. Cl 137/565,ABSTRACT: Apparatus in a heat transfer system or the like. 137/517,138/46 The open end of a duct normally supplied with air at high flow [51] Int. Cl ..Fl6k 17/30, rates iscontrolled by a valve biased to aposition of minimum FOlb /00 restriction. Under conditions of highairflows, a created pres- Field of Search 137/565, sure difference movesthe valve toward a position of maximum 5 l 7, 543; 138/46;244/(lnquired), 57, 1 17.1; restriction. A fan, located in the duct toinduce air flow in the Inquired), 44, 121, 122, 126; absence of thenormal supply, is protected thereby from 230/(lnquired), l 141, 1 146, 115 damage caused by excessive windmilling.

PATENTED AHI 9:971 V LEROY J. SABIN PAUL R.j HUGIHES er 5 THE/I?ATTORNEY INVENTORS FAN PROTECTION VALVE Although not so limited, thisinvention has special reference to heat transfer systems, andparticularly'to means for protecting a fan element is in such a system.

A system in accordance with a preferred aspect of the invention places aheat exchanger in the path of ram air in an aircraft. The ram air actsas a coolant and is carried off or away from the heat exchanger by aduct in which is a normally inactive motor-operated fan. Should it bedesired to begin cooling before the aircraft is in flight, or tocontinue cooling after the aircraft has landed, the fan is set inoperation. It produces an induced flow of air, acting as a coolant inthe absence of ram air. In flight, the fan is inactive and is subject towindmilling under the influence of ram air. Since the ram air may besupplied at high flows windmilling may become excessive and result infan damage.

It is an object of the this invention to reduce the likelihood of fandamage by decreasing the flow rates through the duct during in flightoperation. In carrying out such object there is incorporated in theapparatus a throttling or like valve at the entrance end of the duct.Under the influence of ram air, the throttling valve assumes a positionof maximum restriction relative to the entrance end of the duct. 1n theabsence of pressure differences created by ram air flow, the valve isbiased to and assumes a position of minimum restriction. Accordingly,ram air flow is controlled and restricted to amounts substantiallyreducing the likelihood of excessive fan windmilling. At the same timehowever, the open area of the entrance end of the duct is amplified orrestored to normal during fan operation to make possible adequate airflows without overburdening the fan and motor. I

Other objects and structural details of the invention will appear fromthefollowing description, when read in connection with the accompanyingdrawings, wherein:

FIG. 1 is a detail view, partly broken away, and in side elevation, ofapparatus in accordance with the illustrated embodiment of theinvention, valve means in accordance with the invention being shown infull lines in a position of minimum restriction; and

FIG. 2 is a fragmentary view in longitudinal section, showing the valvein a position of maximum restriction.

Referring to the drawing, apparatus in accordance with illustratedembodiment of the invention provides a manifold secured peripherally toa heat exchanger 11. A frontal surface 12 of the heat exchanger 11 ispresented to an in flowing current of ram air as indicated by arrows 13passing through the heat exchanger. The ram air acts as a coolant withrespect to a second fluid circulated through the heatexchanger by meansincluding end manifolds 14 and 15.

Having passed through the heat exchanger 11, the ram air is establishedin a chamber 16 defined by the manifold 10. There it has access, as willhereinafter more clearly appear to com municating ducts 17 and 18. Themanifold 10 has a central opening 19. The duct 17 has an open flangedend aligning with opening 19 and secured to manifold 10 by. bolts 21..Received in the opening 19 and projecting ininto manifold chamber 16 isa cylindrical part 22,0f a valve assembly 23. The part 22 has a flange24 on one end received between the flanged end of duct 17 and manifold10 and clamped therewith by bolts 21. Vertically and horizontallyintersecting ribs 25 and 36 terminate at the center of part 22 in abearing position 27. A tube 28 has one end thrust into the bearing 27and is welded or otherwise secured thereto. The tube 28 projects axiallythrough and beyond part 22 into the chamber 16. A limit ring 29 isinstalled in its periphery near the outer end.

A poppet type valve 31 slips over tube 28 to be axially reciprocablethereon. A central recessed portion 32 of the valve has an opening 33through which tube 28 is recieved. On the recesses recessed inner faceof portion 32 a nylon bearing member 34 is secured to the valve andachieves a close fitting sliding contact with the exterior of tube 28.Radially outwardly of portion 32, the valve 31 is formed with a radialflange like portion 35 substantially coextensive in diameter with thepart 22 and adapted to approach a seat thereon. The

arrangement is one to define between flangelike valve portion 35 andpart 22 annular open area v36 through which air in chamber 16 has accessto the duct 17. A compression spring 37 adjusts valve 31 outwardly to aposition limiting against ring 29, in which position the valve exertsminimum restriction upon air flow through area 36. Substantially fullycompressed. the valve 31 occupies a position adjacent part 22 reducing aminimum the open space provided by annular area 36.

The duct 18 extends in generally parallel relation to duct 17. 1tcommunicated in with chamber 16 through an opening 39 in manifold 10.The opening 39 is overlaid by a valve plate 41 clamped between a flangedend of duct 18 and the manifold 10 by bolts 42. The plate 41 has anopening registering with opening 39 and is controlled by a flapper-typevalve 43 urged to a closed position by a torsion spring 44. Normallyoccupying a closed position as shown in full lines in FIG. I, the valve43 is movable to an open position as shown in dotted lines by a pressuredifference between chamber 16 and duct 18 sufflcient to overcome spring44.

The duct provides a substantially integral par there part p thereof amotor fan combination including a fan 45 and rotary shaft 46. Themotor-fan combination normally is inactive and shaft 46 and fan 45 arefree to rotate in a windmill fashion as ram air is directed to and flowsthrough duct 17. The valve assembly 23 and in particular valve 31thereof exercises of the fan 45and thereby reducing the likelihood ofdamage.

When the aircraft in on the ground valve 31 is under control of spring37 and therefore assumes a position as shown in full lines in FIG. 1,limiting against ring 29. The valve accordingly is in a position ofminimum airflow restriction. Should it be desired to operate the coolingsystem under these conditions. fan 45 is set in operation. Ambient airthereby is drawn through heat exchanger 11 into manifold chamber 16 andflows through annular passage 36 into duct 17. Air flows generated bythe fan 45 are small in relation to ram air flows so that passage 36remains wide open, allowing fan 45 to work to maximum efficiency. Valve31 will remain seated on ring 29 or may move slightly therefrom underpressure of the inflowing air induced air currents. Under inflightconditions the fan 45 no longer is in a powered rotation but issusceptible of free rotation and if excessive airflows are permitted topass through the duct 17 the involved pressures and windmilling actionof the fan may cause breakage, undue wear and the like. The rarnairflows enter manifold chamber 16 and the pressure difference betweenthe manifold chamber and the interior of duct 17 is applied in a mannerto urge valve 31 toward a position of greater restriction, compressingspring 37. Such closing motion of the valve may be continueduntil itreaches a position substantially as shown in dotted lines in HO. 1 andfull line inFlG. 2 wherein the open area defined by annular passage 36has been substantially reduced. Airflows into the duct 17 accordinglyare held to valuesconsidered not potentially destructive of the fan 45.Excess ram airflows force open valve 43 and at are led away frommanifold chamber 16 by way of duct 18.

A preferred embodiment of the invention has been illustrated but it willbe evident that the invention has other applications, and, thatstructural modifications thereof within the scope of the claims tofollow are possible and contemplated.

I claim:

1. Apparatus interposed in an current of high flow including a ducthaving an entrance end admitting said air current, a normally inactivefan in said duct selectively operable in the absence of said high flowair current to create an induced lower flow air current into saidentrance end of said duct, and flow restriction means positioned at saidentrance end of said duct for protecting said fan from windmillingdamage during high air flows by automatically restricting airflowthrough said duct in response to said higher airflows while fullyaccommodatihg said induced airflows.

2. Apparatus according to claim 1, wherein said flow restricting meansincludes a poppet type valve controlling air flow into'the entrance endof said duct and responding to an air pressure difference to move towarda position of maximum flow restriction, said valve being biased to aposition of minimum restriction.

3. Apparatus according to claim 2. characterized by spring means meansmeans acting as a biasing agent upon said valve and constructed by saidhigh flow air current and to be relatively superior ro pressuredifferences created by the lower flow air current.

4. Apparatus according to claim 1, wherein said flow restricting meansis a valve controlling airflow into the entrance end of said duct andsettable to positions of minimum and maximum restriction, said valveresponding to the high flows of the first mentioned air current to movetoward a position of minimum restriction, said biasing means beingrelative ly unyielding to the lower flows of the inducted air current.

5. Apparatus according to claim 1. wherein said flow restricting meansis a valve adapted to move toward a seat on the entrance end of saidduct to reduce the presented flow area through which air may enter saidduct and movable in the opposite direction to increase such flow areasaid valve being mounted to be responsive to high airflows to reduce theflow area and being biased in the opposite direction.

6 Apparatus according to claim 5. wherein said entrance end of said ductis formed as an open end thereofin the axis of said fan, said valvebeing a poppet type valve mounted in said open end of said duct toreciprocate relatively thereto further characterized by a compressionspring based to urge said valve outwardly away from the said open end ofsaid duct.

7. Apparatus according to claim 5 characterized by a manifold receivingthe airflow and into which said entrance end of said ducts opens, saidmanifold having a relief valve controlled outlet in bypassing relationto said duct to accommodatc air flows supplied to the entrance end ofsaid duct in excess of flows permitted by said valve.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,556,142 Dated: January l9, l9?

Leroy J. Sabin and Paul R. Hughes It is certified that error appears inthe aboveidentified patent and that said Letters Patent are herebycorrected as shown below:

Column 1, line 19, "in flight" should be in-flight line 42 after "with"insert the line 45 "in flowing" should be in-flowir line 70 cancel"recesses" line 74, "flange like" should be flangelike Column 2, line 1,"flangelike" should be flangelike line 2, after "22" insert an line 10,"communicated in" should be communicates line 20, "a substantiallyintegral par there part p" should be as a substantially integral partline 25, after "exercises" insert an automatic control function avoidingexcessive windmilling line 55 "at" should be deleted;

II II Claim 1, line 1, after an insert air last line, after "induced"insert lower Claim 3, line 2, "means means" should be deleted;

line 3, after "constructed" insertto be overcome by pressure differencescreated Claim 4 line 6, after "of" insert maximum restriction, furthercharacterized by biasing means urging said valve toward a position ofClaim 7, line 3, "ducts" should be duct Column 2, line 20, after "duct"insert 17 Signed and sealed this 25th day of May 1971 (SEAL) Attest:

EDWARD M.FLETCHER,JR. WILLIAM E. SCHUYLEI Attesting Officer Commissionerof Pa1

1. Apparatus interposed in an current of high flow including a ducthaving an entrance end admitting said air current, a normally inactivefan in said duct selectively operable in the absence of said high flowair current to create an induced lower flow air current into saidentrance end of said duct, and flow restriction means positioned at saidentrance end of said duct for protecting said fan from windmillingdamage during high air flows by automatically restricting airflowthrough said duct in response to said higher airflows while fullyaccommodating said induced airflows.
 2. Apparatus according to claim 1,wherein said flow restricting means includes a poppet type valvecontrolling airflow into the entrance end of said duct and responding toan air pressure difference to move toward a position of maximum flowrestriction, said valve being biased to a position of minimumrestriction.
 3. Apparatus according to claim 2, characterized by springmeans means means acting as a biasing agent upon said valve andconstructed by said high flow air current and to be relatively superiorro pressure differences created by the lower flow air current. 4.Apparatus according to claim 1, wherein said flow restricting means is avalve controlling airflow into the entrance end of said duct andsettable to positions of minimum and maximum restriction, said valveresponding to the high flows of the first mentioned air current to movetoward a position of minimum restriction, said biasing means beingrelatively unyielding to the lower flows of the inducted air current. 5.Apparatus according to claim 1, wherein said flow restricting means is avalve adapted to move toward a seat on the entrance end of said duct toreduce the presented flow area through which air may enter said duct andmovable in the opposite direction to increase such flow area, said valvebeing mounted to be responsive to high airflows to reduce the flow areaand being biased in the opposite direction. 6, Apparatus according toclaim 5, wherein said entrance end of said duct is formed as an open endthereof in the axis of said fan, said valve being a poppet type valvemounted in said open end of said duct to reciprocate relatively thereto,further characterized by a compression spring based to urge said valveoutwardly away from the said open end of said duct.
 7. Apparatusaccording to claim 5, characterized by a manifold receiving the airflowand into which said entrance end of said ducts opens, said manifoldhaving a relief valve controlled outlet in bypassing relation to saidduct to accommodate air flows supplied to the entrance end of said ductin excess of flows permitted by said valve.